This allows OrangeFS to utilize the dcache and adds an in kernel
attribute cache. We previously used the user side client for this
purpose.
We see a modest performance increase on small file operations. For
example, without the cache, compiling coreutils takes about 17 minutes.
With the patch and a 50 millisecond timeout for dcache_timeout_msecs and
getattr_timeout_msecs (the default), compiling coreutils takes about
6 minutes 20 seconds. On the same hardware, compiling coreutils on an
xfs filesystem takes 90 seconds. We see similar improvements with mdtest
and a test involving writing, reading, and deleting a large number of
small files.
Interested parties can review more data at the following URL.
https://docs.google.com/spreadsheets/d/1v4aUeppKexIbRMz_Yn9k4eaM3uy2KCaPoe_93YKWOtA/pubhtml
The eventual goal of this is to allow getdents to turn into a
readdirplus to the OrangeFS server. The cache will be filled then, which
should provide a performance benefit to the common case of readdir
followed by getattr on each entry (i.e. ls -l).
This also fixes a bug. When orangefs_inode_permission was added, it did
not collect i_size from the OrangeFS server, since this presses an
unnecessary load on the OrangeFS server. However, it left a case where
i_size is never initialized. Then running an executable could fail.
With this patch, size is always collected to be inserted into the cache.
Thus the bug disappears. If this patch is not accepted during this merge
window, we will send a one-line band-aid for this bug instead.
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Merge tag 'for-linus-v4.8' of git://github.com/martinbrandenburg/linux
Pull orangefs update from Martin Brandenburg:
"Kernel side caching and executable bugfix
This allows OrangeFS to utilize the dcache and adds an in kernel
attribute cache. We previously used the user side client for this
purpose.
We see a modest performance increase on small file operations. For
example, without the cache, compiling coreutils takes about 17
minutes. With the patch and a 50 millisecond timeout for
dcache_timeout_msecs and getattr_timeout_msecs (the default),
compiling coreutils takes about 6 minutes 20 seconds. On the same
hardware, compiling coreutils on an xfs filesystem takes 90 seconds.
We see similar improvements with mdtest and a test involving writing,
reading, and deleting a large number of small files.
Interested parties can review more data at the following URL.
https://docs.google.com/spreadsheets/d/1v4aUeppKexIbRMz_Yn9k4eaM3uy2KCaPoe_93YKWOtA/pubhtml
The eventual goal of this is to allow getdents to turn into a
readdirplus to the OrangeFS server. The cache will be filled then,
which should provide a performance benefit to the common case of
readdir followed by getattr on each entry (i.e. ls -l).
This also fixes a bug. When orangefs_inode_permission was added, it
did not collect i_size from the OrangeFS server, since this presses an
unnecessary load on the OrangeFS server. However, it left a case
where i_size is never initialized. Then running an executable could
fail.
With this patch, size is always collected to be inserted into the
cache. Thus the bug disappears. If this patch is not accepted during
this merge window, we will send a one-line band-aid for this bug
instead"
* tag 'for-linus-v4.8' of git://github.com/martinbrandenburg/linux:
Orangefs: update orangefs.txt
orangefs: Account for jiffies wraparound.
orangefs: Change default dcache and getattr timeout to 50 msec.
orangefs: Allow dcache and getattr cache time to be configured.
orangefs: Cache getattr results.
orangefs: Use d_time to avoid excessive lookups
8cbdd85bda
